Process for the copolymerization of alkylene oxides and carbon dioxide using suspensions of multi-metal cyanide compounds

ABSTRACT

A method of forming a polyethercarbonate polyol using a multimetal cyanide compound is disclosed. The method includes providing a multimetal cyanide compound having a crystalline structure and a content of platelet-shaped particles of at least 30% by weight, based on the weight of the multimetal cyanide compound and further including at least two of the following components: an organic complexing agent, water, a polyether, and a surface-active substance. Then an alcohol initiator is reacted with at least one alkylene oxide and carbon dioxide under a positive pressure in the presence of the multimetal cyanide compound, thereby forming the polyethercarbonate polyol.

TECHNICAL FIELD

[0001] The present invention relates to an improved process for thecopolymerization of alkylene oxides and carbon dioxide using multimetalcyanide compounds as catalysts. The present invention permits one toefficiently form polyethercarbonate polyols with better incorporation ofcarbon dioxide into the polyol.

BACKGROUND OF THE INVENTION

[0002] Polyethercarbonate polyols are the polymerization reactionproduct of an initiator, at least one alkylene oxide and carbon dioxide.The carbon dioxide is incorporated into the backbone of the polyolchain. A number of catalyst systems have been used to formpolyethercarbonate polyols with varying degrees of success. Onedifficulty has been the generally low reactivity of carbon dioxide inthe catalytic systems to date, in particular the generally observeddecreasing rate of reaction with increasing CO₂ pressure (L Chen, Rateof regulated copolymerization involving CO₂, J Natural Gas Chemistry,1998, 7, 149-156), thus requiring very high levels of catalyst toproduce any product having incorporation of a significant amount ofcarbon dioxide into the polyol. A second difficulty is the generallyhigh rate of formation of cyclic by products such as propylenecarbonate. Finally, most procedures produce a very viscous producthaving a large degree of polydispersity.

[0003] In an attempt to better control the reaction and to increase thecarbon dioxide incorporation, several forms of double metal cyanide(DMC) complexes have been used in the past. These are disclosed in thefollowing U.S. Pat. Nos. 4,472,560; 4,500,704; 4,826,887; 4,826,952; and4,826,953. These DMC procedures, however, still suffer from slowreaction rates, required high catalyst concentrations and have highlevels of by-product formation. Polyethercarbonate polyols producedusing these DMC catalysts also have high viscosities and high degrees ofpolydispersity. Thus there is a need for an improved catalyst system forpolyethercarbonate polyol formation.

[0004] Most double metal cyanide complexes are amorphous structures andare used in the form of powders. In the present invention it has beenfound that much better results are obtained using crystalline multimetalcyanide compounds in a form which gives them a very high catalyticactivity. In a preferred embodiment crystalline multimetal cyanidecompounds are suspended in organic or inorganic liquids and used ascatalysts in this form. It is particularly advantageous for thesuspended multimetal cyanide compound to have a platelet-likemorphology.

SUMMARY OF THE INVENTION

[0005] In one embodiment, the present invention is a method of forming apolyethercarbonate polyol comprising the steps of: providing amultimetal cyanide compound having a crystalline structure and a contentof platelet-shaped particles of preferably at least 30% by weight, basedon the weight of the multimetal cyanide compound and further comprisingat least two of the following: an organic complexing agent, water, apolyether, and a surface-active substance; and reacting an alcoholinitiator with at least one alkylene oxide and carbon dioxide under apositive pressure in the presence of the multimetal cyanide compound,thereby forming the polyethercarbonate polyol.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0006] In the present invention a unique multimetal cyanide compound isused. The compound is crystalline and preferably has a platelet-likemorphology. In addition, the catalyst is preferably used in the form ofa suspension, which gives it unique activity. The multimetal cyanidecompound of the present invention provides different activity than pastDMC complexes.

[0007] The multimetal compound of the present invention comprises atleast three components. First, at least one multimetal cyanide compoundhaving a crystalline structure and a content of platelet-shapedparticles of at least 30% by weight, based on the multimetal cyanidecompound. Second the compound includes at least two of the followingcomponents: an organic complexing agent, water, a polyether, and asurface-active substance.

[0008] The organic complexing agent comprises, in particular, one of thefollowing: alcohols, ethers, esters, ketones, aldehydes, carboxylicacids, amides, nitrites, sulfides and mixtures thereof.

[0009] As polyethers, use is made, in particular, of polyether alcohols,preferably hydroxyl-containing polyaddition products of ethylene oxide,propylene oxide, butylene oxide, vinyloxirane, tetrahydrofuran,1,1,2-trimethylethylene oxide, 1,1,2,2-tetramethylethylene oxide,2,2-dimethyloxetane, diisobutylene oxide, α-methylstyrene oxide andmixtures thereof.

[0010] As the surface-active substance, use is made, in particular, ofcompounds selected from the group comprising C₄-C₆₀-alcohol alkoxylates,block copolymers of alkylene oxides of differing hydrophilicity,alkoxylates of fatty acids and fatty acid glycerides, block copolymersof alkylene oxides and polymerizable acids and esters.

[0011] The crystalline multimetal cyanide compounds used according tothe present invention are preferably prepared by the following method.First, addition of an aqueous solution of a water-soluble metal salt ofthe formula M¹ _(m)(X)_(n) to an aqueous solution of cyanometalatecompound of the formula H_(a)M²(CN)_(b)(A)_(c). Wherein for the formulaM¹ _(m)(X)_(n): M¹ is at least one metal ion selected from the groupconsisting of Zn²⁺, Fe²⁺, Co³⁺, Ni²⁺, Mn²⁺, Co²⁺, Sn²⁺, Pb²⁺, Fe³⁺,Mo⁴⁺, Mo⁶⁺, Al³⁺, V⁵⁺, Sr²⁺, W⁴⁺, W⁶⁺, Cu²⁺, Cr²⁺, Cr³⁺, Cd²⁺, Hg²⁺,Pd²⁺, Pt²⁺, Vt²⁺, Mg²⁺, Ca²⁺, Ba²⁺, and mixtures thereof; X is at leastone anion selected from the group consisting of halide, hydroxide,sulfate, carbonate, cyanide, thiocyanate, isocyanate, carboxylate, inparticular formate, acetate, propionate or oxalate; and nitrate and mand n are integers which satisfy the valence of M¹, and X. Wherein forthe formula H_(a)M²(CN)_(b)(A)_(c),: M² is at least one metal ionselected from the group consisting of Fe²⁺, Fe³⁺, Co³⁺, Cr³⁺, Mn²⁺,Mn³⁺, Rh³⁺, Ru²⁺, Ru³⁺, V⁴⁺, V⁵⁺, Co²⁺, Ir³⁺, and Cr²⁺ and M² can beidentical to or different from M¹; H is hydrogen or a metal ion, usuallyan alkali metal ion, an alkaline earth metal ion or an ammonium ion; Ais at least one anion selected from the group consisting of halide,hydroxide, sulfate, carbonate, cyanate, thiocyanide, isocyanate,carboxylate and nitrate, in particular cyanide, where A can be identicalto or different from X; and a, b and c are integers selected so that thecyanide compound is electrically neutral.

[0012] In an alternative, one or both aqueous solutions may, if desired,comprise at least one water-miscible, heteroatom-containing ligandselected from the group comprising alcohols, ethers, esters, ketones,aldehydes, carboxylic acids, amides, sulfides or mixtures of at leasttwo of the components mentioned, and at least one of the two solutionscomprises a surface-active substance.

[0013] Also if desired, combination of the aqueous suspension formed inthe first step above can be made with a water-miscible,heteroatom-containing ligand selected from the above-described groupwhich can be identical to or different from the ligand in the firststep.

[0014] In a second step, if desired, the multimetal cyanide compound canbe separated from the suspension.

[0015] The procedure produces platelet-like shaped crystallinemultimetal cyanide compounds. The compounds can have a cubic,tetragonal, trigonal, orthorhombic, hexagonal, monoclinic or tricliniccrystal structure. The definition of the crystal systems describingthese structures and the space groups belonging to the abovementionedcrystal systems may be found in “International tables forcrystallography”, Volume A, editor: Theor Hahn, (1995).

[0016] For the preparation of multimetal cyanide compounds which areused for the suspensions of the present invention, it is advantageous,but not necessary, to use the cyanometalic acid as a cyanometalatecompound, since this does not result in formation of a salt as aby-product.

[0017] These cyanometalic acids (hydrogen cyanometalates), which arepreferably used, are stable and readily handeable in aqueous solution.They can be prepared, for example as described in W. Klemm, W. Brandt,R. Hoppe, Z. Anorg, Allg. Chem. 308, 179 (1961), starting from thealkali metal cyanometalate via the silver cyanometalate and then to thecyanometalic acid. A further possibility is to convert an alkali metalor alkaline earth metal cyanometalate into a cyanometalic acid by meansof an acid ion exchanger, as described, for example, in F. Hein, H.Lilie, Z. Anorg, Allg. Chem. 270, 45 (1952), or A. Ludi, H. U. Güdel, V.Dvorak, Helv. Chim, Acta 50, 2035 (1967). Further possible ways ofsynthesizing the cyanometalic acids may be found, for example, in“Handbuch der Präparativen Anorganischen Chemie”, G. Bauer (editor),Ferdinand Enke Verlag, Stuttgart, 1981. For an industrial preparation ofthese compounds, as is necessary for the process of the presentinvention, the synthesis via ion exchangers is the most advantageousroute. After they have been synthesized, the cyanometalic acid solutionscan be processed further immediately, but it is also possible to storethem for a relatively long period. Such storage should be carried out inthe absence of light to prevent decomposition of the acid.

[0018] The proportion of the acid in the solution should be greater than80% by weight, based on the total mass of cyanometalate complexes,preferably greater than 90% by weight, in particular greater than 95% byweight.

[0019] As heteroatom-containing ligands, use is made of theabove-described organic substances. In a preferred embodiment of thepreparation process, no heteroatom-containing ligand is added to thesolutions in the first step and the addition of heteroatom-containingligand to the suspension of precipitate is also omitted in the secondstep. In a preferred embodiment, only the at least one surface-activecomponent is added, as mentioned above, to one or both of the solutionsin the first step.

[0020] The surface-active compounds used according to the presentinvention can be anionic, cationic, nonionic and/or polymericsurfactants. In particular, nonionic and/or polymeric surfactants areused. Compounds selected from this group are, in particular, fattyalcohol alkoxylates, block copolymers of various epoxides havingdiffering hydrophilicity, castor oil alkoxylates or block copolymers ofepoxides and other monomers, e.g. acrylic acid or methacrylic acid.

[0021] Fatty alcohol alkoxylates used according to the present inventionhave a fatty alcohol comprising 8-36 carbon atoms, in particular 10-18carbon atoms. This is alkoxylated with ethylene oxide, propylene oxideand/or butylene oxide. The polyether part of the fatty alcoholalkoxylate used according to the present invention can consist of pureethylene oxide, propylene oxide or butylene oxide polyethers.Furthermore, it is also possible to use copolymers of two or threedifferent alkylene oxides or else block copolymers of two or threedifferent alkylene oxides. Fatty alcohol alkoxylates which have purepolyether chains are, for example, Lutensol AO grades from BASF AG.Fatty alcohol alkoxylates having block copolymers as polyether part arePlurafac LF grades from BASF Aktiengesellschaft. The polyether chainsparticularly preferably consist of from 2 to 50, in particular from 3 to15, alkylene oxide units.

[0022] Block copolymers as surfactants comprise two different polyetherblocks which differ in their hydrophilicity. Block copolymers which canbe used according to the present invention may comprise ethylene oxideand propylene oxide (Pluronic grades, BASF Aktiengesellschaft). Thewater solubility is controlled via the lengths of the various blocks.The molar masses are in the range from 500 Da to 20,000 Da, preferablyfrom 1,000 Da to 6,000 Da and in particular 1,500-4,000 Da. In the caseof ethylene-propylene copolymers, the proportion of ethylene oxide isfrom 5 to 50% by weight and the proportion of propylene oxide is from 50to 95% by weight.

[0023] Copolymers of alkylene oxide with other monomers which can beused according to the present invention preferably have ethylene blocks.The other monomer can be, for example, butyl methacrylate (PBMA/PEOBE1010/BE1030, Th. Goldschmidt), methyl methacrylate (PMMA/PEOME1010/ME1030, Th. Goldschmidt) or methacrylic acid (EA-300, Th.Goldschmidt).

[0024] The surface-active substances used should have a moderate to goodsolubility in water.

[0025] To prepare the crystalline multimetal cyanide compounds usedaccording to the present invention, an aqueous solution of acyanometalic acid or of a cyanometalate salt is combined with theaqueous solution of a metal salt of the formula M¹ _(m)(X)_(n), wherethe symbols are as defined above. Here, a stoichiometric excess of themetal salt is employed. The molar ratio of the metal ion to thecyanometalate component is preferably from 1.1 to 7.0, more preferablyfrom 1.2 to 5.0 and particularly preferably from 1.3 to 3.0. It isadvantageous to place the metal salt solution in the precipitationvessel first and to add the cyanometalate compound, but the reverseprocedure can also be used. During and after combining the startingsolutions, good mixing, for example by stirring, is necessary.

[0026] The content of the cyanometalate compound in the cyanometalatestarting solution based on the mass of cyanometalate starting solutionis from 0.1 to 30% by weight, preferably from 0.1 to 20% by weight, inparticular from 0.2 to 10% by weight. The content of the metal saltcomponent in the metal salt solution based on the mass of metal saltsolution is from 0.1 to 50% by weight, preferably from 0.2 to 40% byweight, in particular from 0.5 to 30% by weight.

[0027] The surface-active substances are generally added beforehand toat least one of the two solutions. The surface-active substances arepreferably added to the solution which is initially charged in theprecipitation. The content of surface-active substances in theprecipitation solution based on the total mass of the precipitationsuspension is from 0.01 to 40% by weight. Preference is given to acontent of from 0.05 to 30% by weight.

[0028] A further preferred embodiment provides for the surface-activesubstances to be divided proportionately among the two startingsolutions.

[0029] The heteroatom-containing ligands are, in particular, added tothe suspension formed after combination of the two starting solutions.Here too, good mixing has to be ensured.

[0030] It is also possible, however, to add all or some of the ligand toone or both starting solutions. In this case, owing to the change in thesalt solubility, the ligand is preferably added to the solution of thecyanometalate compound.

[0031] The content of the ligand in the suspension formed after theprecipitation should be from 1 to 60% by weight, preferably from 5 to40% by weight, in particular from 10 to 30% by weight.

[0032] The multimetal cyanide compounds used according to the presentinvention preferably have X-ray diffraction patterns as are shown inFIGS. 3 and 4 of DE 197 42 978.

[0033] The multimetal cyanide compounds used for preparing thesuspensions of the present invention preferably comprise primarycrystals having a platelet-like morphology. For the purposes of thepresent invention, platelet-shaped particles are particles whosethickness is one third, preferably one fifth, particularly preferablyone tenth, of their length and width. The preferred catalyst accordingto the present invention contains more than 30% by weight of suchplatelet-shaped crystals, preferably more than 50% by weight,particularly preferably more than 70% by weight and very particularlypreferably more than 90% by weight. The preferred multimetal cyanidecompounds according to the present invention can be seen in scanningelectron micrographs.

[0034] Multimetal cyanide compounds which are less preferred accordingto the present invention are often either in rod form or in the form ofsmall cube-shaped or spherical crystals.

[0035] Depending on how pronounced the platelet character of theparticles is and how many are present in the catalyst, it is possiblethat distinct to strong intensity changes in the individual reflectionsin the X-ray diffraction pattern compared to rod-shaped multimetalcyanide compounds of the same structure will occur.

[0036] The multimetal cyanide compounds produced by precipitationaccording to the above-described process can then be separated from thesuspension by filtration or centrifugation. After the separation, themultimetal cyanide compounds can then be washed one or more times.Washing can be carried out using water, the abovementionedheteroatom-containing ligands or mixtures thereof. Washing can becarried out in the separation apparatus (e.g. filtration apparatus)itself or be carried out in separate apparatuses, by, for example,resuspension of the multimetal cyanide compound in the washing liquidand separating it from the liquid again. This washing can be carried outat from 10° C. to 150° C., preferably from 15 to 60° C.

[0037] The multimetal cyanide compound can subsequently be dried at from30° C. to 180° C. and pressures of from 0.001 bar to 2 bar, preferablyfrom 30° C. to 100° C. and pressures of from 0.002 bar to 1 bar. Dryingcan also be omitted, in which case a moist filter cake is obtained.

[0038] A preferred embodiment of the preparation process for themultimetal cyanide compound used according to the present inventionprovides for no organic, heteroatom-containing ligand, as has beendefined above, apart from the surface-active substance to be addedbefore, during or after the precipitation. In this embodiment of thepreparation process, in which no further organic, heteroatom-containingligands apart from the surface-active substance are used, the multimetalcyanide compound is washed with water after separation from theprecipitation suspension.

[0039] The multimetal cyanide compounds prepared as described above areused in the form of the suspensions of the present invention forpreparing polyethercarbonate polyols.

[0040] Both the moist and the dried multimetal cyanide compounds can beused as starting materials for the suspensions of the present invention.The pulverulent, dried multimetal cyanide compounds are, to prepare thesuspensions of the present invention, dispersed as finely as possible inthe suspension liquid by an efficient dispersion procedure in order toachieve a very high activity of the multimetal cyanide catalyst. Suchmethods of efficiently producing a very finely dispersed suspension are,inter alia, stirring under high shear forces, e.g. in homogenizers orUltraturrax apparatuses, and also the use of dispersion machines, inparticular ball mills and agitated ball mills, e.g. bead mills ingeneral and particularly those having small milling beads (e.g. 0.3 mmdiameter) such as the double-cylinder bead mills (DCP-Super Flow®) fromDraiswerken GmbH, Mannheim, or the centrifugal fluidized bed mills fromNetzsch Gerätebau GmbH, Selb. If desired, dissolvers can be used forpredispersion. Furthermore, small amounts of dispersants known to thoseskilled in the art, e.g. lecithin, zinc oleate or zinc stearate, can beused. In addition, all methods which allow the powder to be dispersedvery finely in liquids are suitable. Dispersion can be carried out atfrom 10° C. to 150° C., preferably from 30° C. to 120° C. Dispersionliquids which can be used are polyethers, organic liquids or water, andalso mixtures thereof.

[0041] As polyethers for the dispersion, it is possible to use compoundshaving molar masses of from 150 to 6,000 dalton and functionalities offrom 1 to 8. Preference is given to using polyethers having molar massesof from 150 to 2,000 dalton and functionalities of from 1 to 3, inparticular molar masses of from 150 to 800 dalton.

[0042] If the predried multimetal cyanide compound is suspended in anorganic liquid, suspensions having solids contents of less than 10% byweight are preferred. Particular preference is given to solids contentsof less than 5% by weight. Organic liquids which can be used areheteroatom-containing compounds and also hydrocarbons or mixturesthereof. Compounds which have a vapor pressure of greater than 0.005 barat 100° C.

[0043] If the predried multimetal cyanide compound is suspended inwater, preference is given to suspensions having solids contents of lessthan 20% by weight and pastes having solids contents of less than 60% byweight. The water content of the pastes and suspensions should then beabove 20% by weight.

[0044] Preference is given to omitting the drying step. In this case,the moist multimetal cyanide compounds are used for preparing thesuspensions of the present invention. For this purpose, a suspension isprepared from the moist multimetal cyanide compound after precipitationand separation of the precipitate from the suspension and after washingof the multimetal cyanide compound, either on the filtration apparatusor externally with filtration being repeated again, but without carryingout a drying step. The multimetal cyanide compound can, as in the caseof the dried multimetal cyanide compounds, be suspended in theabovementioned dispersion media. The methods of preparing a very finelydivided suspension which have been described for the dried multimetalcyanide compounds can also be used for dispersing the undried multimetalcyanide compounds.

[0045] When using moist multimetal cyanide compounds for preparingsuspensions in at least one polyether or a similarly high-boilingliquid, heat and vacuum can, in a preferred embodiment, be appliedsimultaneously during the dispersion step in order to remove volatileconstituents such as water or organic ligands. In the present context,application of vacuum means both the normal vacuum stripping atpressures down to 0.001 bar and also the combination of vacuum treatmentand stripping with inert gases such as nitrogen, argon, helium, etc. Thetemperature in this step can be from 10° C. to 150° C., preferably from30° C. to 120° C.

[0046] In the case of multimetal cyanide suspensions in polyethers,suspensions having solids contents of less than 20% by weight arepreferred. Particular preference is given to solids contents of lessthan 10% by weight, in particular less than 5% by weight. If the undriedmultimetal cyanide compound is suspended in organic liquids, asdescribed above, suspensions having solids contents of less than 10% byweight are preferred. Particular preference is given to solids contentsof less than 5% by weight. If the undried multimetal cyanide compound issuspended in water, suspensions having solids contents of less than 20%by weight and pastes having solids of less than 60% by weight arepreferred. The water content of the pastes and suspensions should thenbe above 20% by weight.

[0047] If the starting materials used for preparing the multimetalcyanide compound are cyanometalic acid and, as the metal salt, a salt ofan acid which has a vapor pressure of greater than 0.005 bar at 100° C.,the suspensions of the present invention can be prepared according tothe following advantageous embodiment. Here, the precipitation iscarried out in the presence of the surface-active agent and optionallythe organic ligand. If an organic ligand is used, the organic ligandshould likewise have a vapor pressure of greater than 0.005 bar at 100°C. After combining the starting material solutions, polyether is addedto the precipitation suspension and the acid formed during theprecipitation, the water and at least part of the organic ligands aredistilled off, if desired under reduced pressure. The remainingsuspension has, according to the present invention, a solids content ofless than 20% by weight and a polyether content of greater than 80% byweight. The possible polyethers are defined above. Preference is givento polyether alcohols having molar masses of from 150 to 2,000 dalton,so that the resulting suspension can be used directly as catalyst forpreparing polyether alcohols.

[0048] The multimetal cyanide suspensions prepared by the methodaccording to the present invention are very useful as catalysts for thesynthesis of polyethercarbonate polyols having functionalities of from 1to 8, preferably from 1 to 4, and number average molar weights of from200 to 20,000. The polyethercarbonate polyols are formed by additionpolymerization of alkylene oxides and carbon dioxide onto H-functionalinitiator substances, like mono-alcohols and poly-aclohols.

[0049] To prepare polyethercarbonate polyols using the catalysts of thepresent invention, it is possible to employ a large number of compoundshaving at least one alkylene oxide group, for example ethylene oxide,1,2-epoxypropane, 1,2-methyl-2-methylpropane, 1,2-epoxybutane,2,3-epoxybutane, 1,2-methyl-3-methylbutane, 1,2-epoxypentane,1,2-methyl-3-methylpentane, 1,2-epoxyhexane, 1,2-epoxyheptane,1,2-epoxyoctane, 1,2-epoxynonane, 1,2-epoxydecane, 1,2-epoxyundecane,1,2-epoxydodecane, styrene oxide, 1,2-epoxycyclopentane,1,2-epoxycyclohexane, (2,3-epoxypropyl)-benzene, vinyloxirane,3-phenoxy-1,2-epoxypropane, 2,3-epoxy (methyl ether), 2,3-epoxy (ethylether), 2,3-epoxy (isopropyl ether), 2,3-epoxy-1-propanol,3,4-epoxybutyl stearate, 4,5-epoxypentyl acetate, 2,3-epoxy propylmethacrylate, 2,3-epoxypropyl acrylate, glycidol butyrate, methylglycidate, ethyl 2,3-epoxybutanoate, 4-(trimethylsilyl)butane1,2-epoxide, 4-(trimethylsilyl)butane 1,2-epoxide,3-(perfluoromethyl)propene oxide, 3-perfluoromethyl)propene oxide,3-(perfluorobutyl)propene oxide, and also any mixtures of at least twoof the abovementioned compounds.

[0050] The desired carbon dioxide content of the polyethercarbonatepolyol is preferably from 1 to 30%, more preferably from 2 to 20%, andmost preferably from 5 to 15%, based on weight % of CO₃ of thepolyethercarbonate polyol. The catalyst concentrations employed are lessthan 1% by weight, preferably less than 0.5% by weight, particularlypreferably less than 1,000 ppm, very particularly preferably less than500 ppm and especially preferably less than 100 ppm, based on the totalmass of the polyethercarbonate polyol. The polyethercarbonate polyolscan be prepared either batchwise, semi-continuously or fullycontinuously. The process temperatures which can be employed in thesynthesis are in the range from 40° C. to 180° C., with preference beinggiven to temperatures in the range from 90° C. to 130° C. Temperaturesabove 180° C. may result in catalyst decomposition and thus reducecatalyst activity.The carbon dioxide pressure during the reactioninfluences the amount of carbon dioxide incorporation. The carbondioxide pressure may vary widely and range from 10 to 3,000 pounds persquare inch (psi), preferably from 90 to 2,500 psi, and more preferablyfrom 90 to 2,000 psi.

[0051] To prepare the polyethercarbonate polyols using the catalysts ofthe present invention, it is possible to employ other typical polyolinitiator compounds preferably those having at least one alkylene oxidegroup. Suitable initiator compounds include alkanols such as butanol,diols, such as butane diol, glycols such as dipropylene glycol, glycolmonoalkyl ethers, aromatic hydroxy compounds, trimethylol propane, andpentaerythritol. Preferably the initiator should include one or morealkylene oxide groups for the catalyst to function efficiently. Thus,preferably the initiator is first reacted with at least one alkyleneoxide to form an oligomer prior to it use to form the polyethercarbonatepolyol. Examples include glycerine having from 1 to 6 propylene oxidesattached to it, propylene glycol having 1 to 6 propylene oxides,trimethyl propane with 1 to 6 propylene oxides, dipropylene glycol withone or more alkylene oxides attached, sucrose with one or more alkyleneoxides attached, sorbitol with one or more alkylene oxides attached, andblends of these oligomers. As would be understood by one of ordinaryskill in the art, the oligomer can be reacted with either the samealkylene oxide used during its formation or with another alkylene oxidein the polyethercarbonate polyol formation reaction. The presentinvention also relates to the preparation of polyurethane formingcompositions based on the herein described polyethercarbonate polyolsand to polyurethane compounds obtained from said polyurethane formingcompositions.To obtain polyurethane compounds, polyethercarbonatepolyols may be reacted with compounds which are used in conventionalpolyurethane forming compositions for the preparation of polyurethanes,such as isocyanates, catalysts, blowing agents, stabilizers, etc.

[0052] The isocyanates that may be used include isomers and derivativesof toluene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI).The reaction between the hydroxyl and the isocyanate groups may becatalyzed by tertiary amine catalysts and/or organic tin compounds suchas stannous octoate and dibutyltin dilaureate. To obtain a foamedpolyurethane, blowing agents may be employed. In addition, stabilizersand flame retardants may be added.

EXAMPLES

[0053] A multimetal cyanide catalyst according to the present inventionwas prepared as described above. Several comparative DMC catalysts wereprepared as described below to illustrate the usefulness of the presentcatalyst compared to typical DMC catalysts.

[0054] Preparation of Hexacyanocobaltic Acid

[0055] An amount of 7 liters of strong acid ion exchanger in the sodiumform (Amberlite® 252 Na, Rohm & Haas) was introduced into an ionexchange column (length: 1 m, volume: 7.7 1). The ion exchanger wassubsequently converted into the H form by passing 10% strengthhydrochloric acid through the ion exchange column for 9 hours at a rateof 2 bed volumes per hour, until the sodium content of the dischargedsolution was less than 1 ppm. The ion exchanger was subsequently washedwith water until neutral. The regenerated ion exchanger was then used toprepare a hexacyanocobaltic acid which was essentially free of alkalimetal. For this purpose, a 0.24 molar solution of potassiumhexacyanocobaltate in water was passed through the ion exchanger at arate of 1 bed volume per hour. After 2.5 bed volumes, the feed waschanged from potassium hexacyanocobaltate solution to water. The 2.5 bedvolumes obtained had an average hexacyanocobaltic acid content of 4.5%by weight and alkali metal contents of less than 1 ppm. Thehexacyanocobaltic acid solutions used for the further examples werediluted appropriately with water.

[0056] Preparation of a Multimetal Cyanide Compound Catalyst Suspension

[0057] An amount of 479.3 g of an aqueous zinc acetate solution (13.8 gof zinc acetate dihydrate and 2.2 g of polyether Pluronic® PE 6200 (BASFAktiengesellschaft) dissolved in 150 g of water) were heated to 50° C.While stirring (screw stirrer, stirring energy input: 1W/l), 558 g of anaqueous hexacyanocobaltic acid solution (cobalt content: 9 g/l, 1.5% byweight of Pluronic® PE 6200 (BASF Aktiengesellschaft), based on thehexacyanocobaltic acid solution) were then metered in over a period of20 minutes. After all the hexacyanocobaltic acid solution had beenmetered in, the mixture was stirred for a further 5 minutes at 50° C.The temperature was subsequently reduced to 40° C. over a period of onehour. The precipitated solid was separated from the liquid by means of apressure filter and washed with water. The moist filter cake wassubsequently dispersed in the amount of liquid required to give a 5%strength by weight multimetal cyanide suspension.

[0058] Preparation of Comparative DMC Catalysts

[0059] Comparative DMC catalyst example one was prepared as follows. Afirst solution was prepared by dissolving an amount of 50 grams (g) ofK₃[Co(CN)₆], 0.15 moles, in 1200 milliliters (mL) of H₂O and 140 mLtert-butyl alcohol. The first solution was added to a 3 Liter, 4-neckround bottom flask equipped with a stirrer and a thermometer, and warmedto 40° C. A second solution was prepared comprising 51 g of ZnCl₂, 0.375moles, dissolved in 200 mL H₂O and 15 mL of tert-butyl alcohol. TheZnCl₂ solution was added dropwise, with stirring (80 rpm), with a flowof 2-3 drops/second to the first solution. After the addition wascomplete, the suspension was stirred at 40° C. for 2 additional hours.The suspension was allowed to settle overnight, filtered, and washed.The washes were as follows in the order given: deionized H₂O(4×75 mLH₂O); 75 mL 25% tert-butyl alcohol in H₂O; 75 mL 1:1 tert-butyl alcoholin H₂O; and 75 mL tert-butyl alcohol. Then 1.5-2 g of precipitate wasrecrystallized from 30 mL H₂O and 5 mL tert-butyl alcohol (60° C., 3 h).The precipitate was filtered as before. The final precipitate was driedin a vacuum oven, at 60° C. for 6-8 h.

[0060] Comparative DMC catalyst example two was prepared as describedabove for comparative example one up to the recrystallization step. Anamount of 1.5 to 2.0 g of precipitate was recrystallized from ZnCl₂ (0.3g, 0.0012 mol) dissolved in 30 mL H₂O and 5 mL tert-butyl alcohol (60°C., 3 h). The final precipitate was filtered as before and dried in thevacuum oven, at 60° C. for 6-8 h.

[0061] Comparative DMC catalyst examples three and four were bothprepared using the free hexacyanocobaltic acid H₃[Co(CN)₆], obtainedfrom K₃[Co(CN)₆] which had been passed through an ion exchange column.The column and H₃[Co(CN)₆] were prepared as follows. The ion exchangeresin was Amberlyst 15, wet form from Aldrich Chemical Company, Inc.Milwaukee, Wis., USA. An amount of 175 g of wet resin (52-57% H₂O, 4.7eq./kg) was suspended in 400 mL deionized H₂O. This provided0.175×4.7×0.48=0.39 eq. for the column to be able to easily exchange 20g of K₃[Co(CN)₆] (# eq. K⁺ (20×3)/332.35=0.18). The column was preparedby placing glass wool at the bottom of the column, followed by a bed ofglass beads. The resin was carefully placed in the column, and most ofthe H₂O drained until the water was level with the top of column. Then10% HCl (150 mL=one bed volume) was added. The rate of solution passingthrough the column should be 1 bed volume in 15 min (3-4 drops/second),until the acid solution is level with top of column. The acid wash wasfollowed by H₂O washings (minimum 3-4, to pH>4). The first 2 bed volumes(150 mL) of H₂O washing were at a rate of 4 bed volumes/hour (3-4drops/second), followed by a rate of 10-12 bed volumes/hour (12drops/second) for the remaining washings. There was always 1-2 inches ofliquid on top of the resin.

[0062] Comparative DMC catalyst three was prepared as follows. Asolution was prepared by dissolving 20 g of K₃[Co(CN)₆] (0.06 mol) in150 mL deionized H₂O. The solution was carefully poured on top of thecolumn. A second solution was prepared by dissolving 10.25 g of ZnCl₂(0.075 mol) in 100 mL water +100 mL tert-butyl alcohol in a 2,000 mL4-neck flask. The solution was warmed with stirring to 40° C. Then theH₃[Co(CN)₆] from the ion exchange column was added at 3 drops/sec, total15 minutes, to the flask. The flow was stopped before the column randry. Then 2×150 mL of water was added to the column and thecorresponding column volumes were added to the flask. Then 150 mL ofwater was added to the column and the column was flushed fast at 12drops/sec. The pH of the solution coming out of the column at this pointmust be >4. The suspension formed in the 2,000 mL flask was stirred at40° C. for 2 more hours. The suspension was filtered through a finefritted funnel. The precipitate was collected and washed with deionizedH₂O (4×75 mL) followed by 75 mL 25% tert-butyl alcohol in H₂O, 75 mL 1:1tert-butyl alcohol in H₂O and 75 mL tert-butyl alcohol. About 2 g offiltercake material was placed into a 100 mL wideneck flask with amagnetic stirrer. Then 30 mL of water and 5 mL tert-butyl alcohol wasadded and the suspension stirred at 60° C. for 3 hrs. The suspension wascooled to room temperature and filtered. The filtrate was washed withtert-butyl alcohol. The filter cake was transferred to a drying dish anddried in a vacuum oven at 60° C. for >10 hrs. The dried cake was placedin a dessicator over P₂O₅. The final cake was ground into powder ifnecessary.

[0063] Comparative DMC catalyst four was prepared as follows. A solutionwas prepared by dissolving 20 g of K₃[Co(CN)₆] (0.06 mol) in 150 mLdeionized H₂O. The solution was carefully poured on top of the column. Asecond solution was prepared by dissolving 10.25 g of ZnCl₂ (0.075 mol)in 100 mL water in a 2,000 mL 4-neck flask. The solution was warmed withstirring to 40° C. Then the H₃[Co(CN)₆] from the ion exchange column wasadded at 3 drops/sec, total 15 minutes, to the flask. The flow wasstopped before the column ran dry. Then 2×150 mL of water was added tothe column and the corresponding column volumes were added to the flask.Then 150 mL of water was added to the column and the column was flushedfast at 12 drops/sec. The pH of the solution coming out of the column atthis point must be >4. The suspension formed in the 2,000 mL flask wasstirred at 40° C. for 2 more hours. The suspension was filtered througha fine fritted funnel. The precipitate was washed with deionized H₂O(4×75 mL). About 2 g of filtercake material was placed into a 100 mLwideneck flask with a magnetic stirrer. Then 20 mL of water and 10 mL ofpolyether polyol, an adduct of glycerine and propylene oxide monomerwith a molecular weight of 422, was added and the suspension stirred at60° C. for 3 hrs. The suspension was cooled to room temperature andfiltered. The filtrate was washed with the same mixture of water andpolyether polyol. The filter cake was transferred to a drying dish anddried in a vacuum oven at 60° C. for >10 hrs. The dried cake was placedin a dessicator over P₂O₅. The final cake was ground into powder ifnecessary.

[0064] Preparation of Polyethercarbonate Polyols

[0065] The multimetal cyanide compound of the present invention and thecomparative DMC catalysts, described above, were used to preparepolyethercarbonate polyols using a general procedure described below.

[0066] A clean and dry 300 ml autoclave, equipped with an agitator,external heating, internal cooling via a cooling coil, a propylene oxidefeed line, a carbon dioxide gas feed line, a temperature sensor and apressure sensor, was charged with 70 g of a purified initiator polyoland the DMC catalyst of interest. The initiator used in theseexperiments was an adduct of glycerine and propylene oxide monomer witha number average molecular weight of 730, a water content <0.03% and aresidual catalyst content <5 ppm. The initiator-catalyst mixture washeated to 130° C. under vacuum (<1 mm Hg) for 2 hours to remove anyresidual moisture. The vacuum system was disconnected and the reactorpressurized to 0 psi using Argon gas. Then 5 g of propylene oxide wasadded and the pressure increase in the reactor was monitored. Within15-30 minutes the reactor pressure declines back to 0 psi, indicatingthat the DMC catalyst has been activated and is now active. Then 170 gpropylene oxide (PO) monomer is added at 130° C. at a constant rate of 1g/min. After 5 minutes of the PO feed, the reactor was pressurized withCO₂ gas (Air Products, research grade) for the duration of the PO feed.Following the completion of the PO addition step, unreacted monomer wasleft to react out at 130° C. The reactor was then vented and cooled andthe product collected. The peak molecular weight and the weight averagemolecular weight were determined by gel permeation chromatography. Theviscosity was measured using a Brookfield DV-III rheometer. Thecarbonate content of the polymer was determined by IR (peak at 1745cm-1) and calculated as weight % CO₃ in the polymer. Propylene carbonateformed as a by-product was not removed.

[0067] Polyethercarbonate polyol example one according to the presentinvention was prepared using the multimetal cyanide compound preparedaccording to the present invention and the procedure described above asfollows. An amount of 0.5 g of a suspension of the multimetal cyanidecompound catalyst, 5% in a purified initiator polyol, which is an adductof glycerine and propylene oxide monomer with a number average molecularweight 730, equal to 0.025 g of catalyst was used. The reactiontemperature was 120° C. and the reactor was pressurized with CO₂ to 500psi. The yield of the reaction product obtained was 273 g. Its peakmolecular weight was 1,724, its weight average molecular weight 3,081.The product had a polydispersity Mw/Mn of 1.63. The polydispersity of apolyol is the weight average molecular weight (Mw) divided by the numberaverage molecular weight (Mn). It is an indication of the breadth of themolecular weight distribution. A monodispersed polyol would have a valueof 1.0. The viscosity of the product was 1,983 centipoise at 25° C. Thecarbonate content of the polyethercarbonate polyol was 9.3%.

[0068] Polyethercarbonate polyol example two according to the presentinvention was prepared similarly to example one except for the reactiontemperature. The reaction temperature was 110° C. and the reactor waspressurized with CO₂ to 500 psi. The yield of the reaction productobtained was 283 g. Its peak molecular weight was 1,801, its weightaverage molecular weight 3,567. The product had a polydispersity Mw/Mnof 1.69. The viscosity of the product was 2,675 centipoise at 25° C. Thecarbonate content of the polyethercarbonate polyol was 11.4%.

[0069] In polyethercarbonate polyol example three according to thepresent invention the multimetal catalyst according to the presentinvention was used as a solid powder. An amount of 0.2 g of themultimetal catalyst powder was used.. The reaction temperature was 110°C. and the reactor was pressurized with CO₂ to 900 psi. The yield of thereaction product obtained was 284 g. Its peak molecular weight was 1,755and its weight average molecular weight was 4,899. The product had apolydispersity Mw/Mn of 1.73. The viscosity of the product was 1,840centipoise at 25° C. The carbonate content of the polyethercarbonatepolyol was 13.2%.

[0070] Comparative polyethercarbonate polyol example one was preparedusing comparative DMC catalyst one. An amount of 0.1 g of thecomparative DMC catalyst example one was used as a solid powder, thereaction temperature was 130° C. and the reactor was pressurized withCO₂ to 900 psi. The yield of the reaction product obtained was 255 g.The product showed a bimodal molecular weight distribution with peakmolecular weights at 810 and 6,896. Its weight average molecular weightwas 14,537. Its polydispersity Mw/Mn was 2.99. The viscosity of theproduct was 11,225 centipoise at 25° C. The carbonate content of thepolyol produced was 10.1%. Thus, by way of contrast this DMC catalystproduces a polyethercarbonate polyol product having a very broadmolecular weight distribution and a much higher viscosity.

[0071] Comparative polyethercarbonate example two was prepared usingcomparative DMC catalyst one. An amount of, 0.1 g of the comparative DMCcatalyst example 1 was used as a solid powder, the reaction temperaturewas 150° C. and the reactor was pressurized with CO₂ to 900 psi. Theyield of the reaction product obtained was 255 g. The product showed amultimetal molecular weight distribution with a peak molecular weight at4,211 and a weight average molecular weight of 6,156. Its polydispersityMw/Mn was 2.53. The viscosity of the product was 1,305 centipoise at 25°C. The carbonate content of the polyol was 6.3%. Thus, even if thereaction temperature is increased the product is not as satisfactory.The product has a beneficially lower viscosity, but also a much lowercarbonate content.

[0072] Comparative polyethercarbonate example three was prepared usingcomparative DMC catalyst one. An amount of, 0.5 g of the comparative DMCcatalyst example 1 was used as a solid powder, the reaction temperaturewas 105° C. and the reactor was pressurized with CO₂ to 900 psi. Theyield of the reaction product obtained was 228 g. The product showed abimodal molecular weight distribution with peak molecular weights at 816and 5,154. The weight average molecular weight was 7,868. Itspolydispersity Mw/Mn was 3.85. The viscosity of the product was 12,138centipoise at 25° C. The carbonate content of the polyol was 13.2%.Thus, while employing a significantly increased catalyst concentrationwhile at the same timelowering the reaction temperature increased thecarbonate content, but it also reduced the yield and significantlyincreased the viscosity of the product.

[0073] For comparative polyethercarbonate polyol four, 0.2 g of thecomparative DMC catalyst two was used as a solid powder. The reactiontemperature was 130° C. and the reactor was pressurized with CO₂ to 900psi. The yield of the reaction product obtained was 261 g. The productshowed a multimetal molecular weight distribution with a peak molecularweight at 4,016 and a weight average molecular weight of 5,866. Itspolydispersity Mw/Mn was 2.37. Its carbonate content was 7.6%. Theviscosity of the product was 3,857 centipoise at 25° C. Thus, thiscomparative catalyst produced a polyethercarbonate polyol with a broadmolecular weight distribution, low yield, and higher viscosity.

[0074] For comparative polyethercarbonate polyol five, 0.2 g of thecomparative DMC catalyst three was used as a solid powder. The reactiontemperature was 130° C. and the reactor was pressurized with CO₂ to 900psi. The yield of the reaction product obtained was 260 g. The productshowed a bimodal molecular weight distribution with a peak molecularweight of 794 and a weight average molecular weight of 6,648. Itspolydispersity Mw/Mn was 3.36. The viscosity of the product was 3,700centipoise at 25° C. The carbonate content of the PEC polyol was 8.5%.Thus, this comparative DMC catalyst also produced a broad molecularweight distribution, low yield and a high viscosity.

[0075] For comparative polyethercarbonate polyol six, 0.2 g of thecomparative DMC catalyst four was used as a solid powder. The reactiontemperature was 130° C. and the reactor was pressurized with CO₂ to 900psi. The yield of the reaction product obtained was 180 g. The productshowed a broad molecular weight distribution with a peak molecularweight at 819 and a weight average molecular weight of 7,878. Itspolydispersity Mw/Mn was 5.52. Its carbonate content was 6.9%. Theviscosity of the product was 635 centipoise at 25° C. Thus, thiscomparative DMC catalyst produced a low yield of the desiredpolyethercarbonate polyol product as a result of an incomplete reaction.

[0076] Scaled Up Preparation of Polyethercarbonates

[0077] In the next series of experiments, the polyethercarbonate polyolformation reaction was scaled up to a larger two gallon autoclave usinga multimetal cyanide compound prepared according to the presentinvention. The general procedure was as described below. A clean and dry2 gallon autoclave, equipped with an agitator, external heating,internal cooling via a cooling coil, a PO feed line, a gas feed line, atemperature sensor and a pressure sensor, was charged with a purifiedinitiator polyol, described above, and the multimetal cyanide compoundcatalyst prepared according to the present invention.. Theinitiator-catalyst mixture is heated to 130° C. under vacuum (<1 mm Hg)for 2 hours to remove any residual moisture. The vacuum system isdisconnected and the reactor pressurized to 0 psi using Argon gas. Then200 g of propylene oxide is added and the pressure increase in thereactor is monitored. Within 15-30 minutes the reactor pressure declinesback to 0 psi, indicating that the multimetal cyanide compound catalystis active. An amount of 2,500 g of PO monomer is then added at 130° C.at a constant rate over 3 hours. At 10 minutes after commencement of thePO feed, the reactor is pressurized with CO₂ gas (Air Products, researchgrade) for the duration of the PO feed and the PO reaction. Followingthe completion of the PO addition step, unreacted monomer is left toreact out at 130° C. The reactor is then vented and cooled and theproduct collected. The peak molecular weight and the weight averagemolecular weight were determined by gel permeation chromatography. Theviscosity was measured using a Brookfield DV-III rheometer. Thecarbonate content of the polymer was determined by IR (peak at 1745cm-1) and calculated as weight % CO₃ in the polymer. The product wasfiltered using 3% diatomaceous earth filter aid. Propylene carbonateformed as a by-product was removed.

[0078] Polyethercarbonate polyol example four prepared according to thepresent invention was prepared as follows. An amount of 1,000 g of thepurified initiator polyol, described above, and 20 g of a suspension ofthe DMC catalyst, 5% in the purified initiator polyol, which is 0.025 gcatalyst, were used. The reaction temperature was 130° C. and thereactor was pressurized with CO₂ to 1,134 psi through the slow additionof 1,000 g CO₂. The yield of the reaction product obtained was 4,055 g.Its peak molecular weight was 1,778 and its weight average molecularweight was 4,077. Its polydispersity Mw/Mn was 1.62. The viscosity ofthe crude product was 2,635 centipoise at 25° C. The viscosity of theproduct after propylene carbonate removal was 4,870 centipoise at 25° C.The carbonate content of the polyethercarbonate polyol was 9.9%.

[0079] Polyethercarbonate polyol example five prepared according to thepresent invention was prepared as follows. An amount of 900 g of thepurified initiator polyol and 20 g of a suspension of the DMC catalyst,described above, were used. The reaction temperature was 110° C. and thereactor was pressurized with CO₂ to 200 psi. The yield of the reactionproduct obtained was 3,564 g. Its peak molecular weight was 2,562 andits weight average molecular weight was 3,057. Its polydispersity Mw/Mnwas 1.16. The viscosity of the crude product was 760 centipoise at 25°C. The carbonate content of the polyethercarbonate polyol was 2.6%.

[0080] Polyethercarbonate polyol example six prepared according to thepresent invention was prepared as follows. An amount of 1,000 g of thepurified initiator polyol and 20 g of a suspension of the DMC catalyst,described above, were used. The reaction the reaction temperature was130° C. and the reactor was pressurized with CO₂ to 500 psi. The yieldof the reaction product obtained was 3,859 g. Its peak molecular weightwas 2,111 and its weight average molecular weight was 2,990. Itspolydispersity Mw/Mn was 1.26. The viscosity of the crude product was1,230 centipoise. at 25° C. The carbonate content of thepolyethercarbonate polyol was 5.8%.

[0081] Polyethercarbonate polyol example seven prepared according to thepresent invention was prepared as follows. An amount of 900 g of thepurified initiator polyol and 20 g of a suspension of the DMC catalyst,described above, were used. The reaction the reaction temperature was110° C. and the reactor was pressurized with CO₂ to 700 psi. The yieldof the reaction product obtained was 4,156 g. Its peak molecular weightwas 2,056 and its weight average molecular weight was 3,694. Itspolydispersity Mw/Mn was 1.39. The viscosity of the crude product was2,510 centipoise at 25° C. The carbonate content of thepolyethercarbonate polyol was 11.9%.

[0082] Polyethercarbonate polyol example eight prepared according to thepresent invention was prepared as follows. An amount of 900 g of thepurified initiator polyol and 20 g of a suspension of the DMC catalyst,described above, were used. The reaction the reaction temperature was110° C. and the reactor was pressurized with CO₂ to 1490 psi The yieldof the reaction product obtained was 4,473 g. Its peak molecular weightwas 1,839 and its weight average molecular weight was 3,755. Itspolydispersity Mw/Mn was 1.46. The viscosity of the crude product was5,170 centipoise at 25° C. The carbonate content of thepolyethercarbonate polyol was 16.9%.

[0083] Polyethercarbonate polyol example nine prepared according to thepresent invention was prepared as follows. An amount of 900 g of thepurified initiator polyol and 20 g of a suspension of the DMC catalyst,described above, were used. The reaction the reaction temperature was110° C. and the reactor was pressurized with CO₂ to 2410 psi. The yieldof the reaction product obtained was 4,661 g. Its peak molecular weightwas 1,941 and its weight average molecular weight was 4,162. Itspolydispersity Mw/Mn was 1.58. The viscosity of the crude product was6,450 centipoise at 25° C. The carbonate content of thepolyethercarbonate polyol was 18.9%.

[0084] Examples five through nine clearly show how using the multimetalcyanide compound catalysts described herein, CO₂ incorporation into thedesired polyethercarbonate polyol products can readily be controlled viathe CO₂ pressure. The yield and carbonate content increase withincreasing CO₂ pressure. Catalyst activity does not decrease withincreasing carbon dioxide load, the same low concentration of themultimetal cyanide compound catalyst is used throughout the series ofincreasing CO₂ pressure and corresponding carbonate content. Inaddition, poydispersities and viscosities of the polyethercarbonatepolyol products remain low even at increasing CO₂ process pressure andcorresponding increasing CO₂ incorporation rates. The examples onethrough nine clearly demonstrate the superiority of the presentmultimetal cyanide compound in the formation of polyethercarbonatepolyolss versus a variety of previous DMC catalysts.

[0085] Preparation of a Foam Using a Polyethercarbonate Polyol

[0086] In a final comparative test the polyethercarbonate polyol ofexample four above was compared to a standard polyether alcohol in theformation of a flexible polyurethane foam. The standard polyetheralcohol was a glycerine propylene oxide adduct having a molecular weightof 2,640. The resin component of each foam was premixed and then theisocyanate component was added with intensive mixing. The reaction timesand a variety of foam properties were compared. The resin component foreach was as follows: 400.00 g of polyol, 1.00 g of Dabco® 33-LVcatalyst, 4.00 g of BF-2370 silicone foam stabilizer, 16.00 g of waterand 1.80 g of stannous octoate catalyst T-10 for a total resin weight of422.80 g. The isocyanate used was toluene diisocyanate(2,4-toluenediisocyanate: 2,6-toluenediisocyanate=80:20) in an amount of210.3 g. Each foam had a mix time of 8 seconds and a cream time of 9seconds. The foam prepared with the polyethercarbonate polyol had a risetime of 93 seconds. The foam prepared with the comparative polyetheralcohol had a rise time of 90 seconds. Both foams were subsquently keptat a temperature of 200° F. for a period of 24 hours. The physicalproperties of the foams are presented below in Table 1. The foamprepared with the polyethercarbonate polyol had improved propertiescompared to the foam made with the polyether alcohol. TABLE 1Polyethercarbonate Polyether Property polyol foam alcohol foam Density,pounds per cubic 1.45 1.47 foot Hardness 25% IFD, lbf 38.9 40.5 Hardness65% IFD, lbf 75.9 74.6 Air flow, cubic foot per 5.0 3.9 meter Originalpeak tensile, psi 13.4 12.6 Heat aged peak tensile, psi 16.5 14.1Original 50% CFD, psi 0.66 0.64 Humid aged 50% CFD, psi 0.64 0.59 Humidaged CFD (% of 96.7 91.3 Original)

[0087] While the preferred embodiment of the present invention has beendescribed so as to enable one skilled in the art to practice the presentinvention, it is to be understood that variations and modifications maybe employed without departing from the concept and intent of the presentinvention as defined in the following claims. The preceding descriptionis intended to be exemplary and should not be used to limit the scope ofthe invention. The scope of the invention should be determined only byreference to the following claims.

1. A method of forming a polyethercarbonate polyol comprising the stepsof: a) providing a multimetal cyanide compound having a crystallinestructure and a content of platelet-shaped particles of at least 30% byweight, based on the weight of the multimetal cyanide compound andcomprising at least two of the following: an organic complexing agent,water, a polyether, and a surface-active substance; and b) reacting analcohol initiator with at least one alkylene oxide and carbon dioxideunder a positive pressure in the presence of the multimetal cyanidecompound, thereby forming a polyethercarbonate polyol.
 2. The method ofclaim 1, wherein step b) comprises reacting an alcohol initiator havinga functionality of from 1 to 8 with at least one alkylene oxide andcarbon dioxide under a positive pressure in the presence of saidmultimetal cyanide compound.
 3. The method of claim 1, wherein step b)comprises reacting an alcohol initiator having a functionality of from 1to 4 with at least one alkylene oxide and carbon dioxide under apositive pressure in the presence of said multimetal cyanide compound.4. The method of claim 1, wherein step b) comprises reacting an alcoholinitiator having a functionality of from 1 to 8 with at least one firstalkylene oxide to form an oligomer and then reacting the oligomer withat least one second alkylene oxide and carbon dioxide under a positivepressure in the presence of said multimetal cyanide compound.
 5. Themethod of claim 1, wherein step b) comprises reacting an alcoholinitiator with a plurality of alkylene oxides and carbon dioxide under apositive pressure in the presence of said multimetal cyanide compound.6. The method of claim 1, wherein step b) comprises reacting an alcoholinitiator with propylene oxide and carbon dioxide under a positivepressure in the presence of said multimetal cyanide compound.
 7. Themethod of claim 1, wherein step b) comprises reacting an alcoholinitiator with at least one alkylene oxide and carbon dioxide under apositive pressure of from 10 to 3,000 psi in the presence of saidmultimetal cyanide compound.
 8. The method of claim 1, wherein step b)comprises reacting an alcohol initiator with at least one alkylene oxideand carbon dioxide under a positive pressure of from 90 to 2,500 psi inthe presence of said multimetal cyanide compound.
 9. The method of claim1, wherein step b) comprises reacting an alcohol initiator with at leastone alkylene oxide and carbon dioxide under a positive pressure of from90 to 2,000 psi in the presence of said multimetal cyanide compound. 10.The method of claim 1, wherein step b) comprises reacting an alcoholinitiator with at least one alkylene oxide and carbon dioxide under apositive pressure in the presence of said multimetal cyanide compound ata temperature of from 40 to 180° C.
 11. The method of claim 1, whereinstep b) comprises reacting an alcohol initiator with at least onealkylene oxide and carbon dioxide under a positive pressure in thepresence of said multimetal cyanide compound at a temperature of from 90to 130° C.
 12. The method of claim 1, wherein step b) comprises reactingan alcohol initiator with at least one alkylene oxide and carbon dioxideunder a positive pressure in the presence of said multimetal cyanidecompound to produce a polyethercarbonate polyol having a carbonatecontent of from 1 to 30% calculated as the weight percent CO₃ in thepolyethercarbonate polyol.
 13. The method of claim 1, wherein step b)comprises reacting an alcohol initiator with at least one alkylene oxideand carbon dioxide under a positive pressure in the presence of saidmultimetal cyanide compound to produce a polyethercarbonate polyolhaving a carbonate content of from 2 to 20% calculated as the weightpercent CO₃ in the polyethercarbonate polyol.
 14. The method of claim 1,wherein step b) comprises reacting an alcohol initiator with at leastone alkylene oxide and carbon dioxide under a positive pressure in thepresence of said multimetal cyanide compound to produce apolyethercarbonate polyol having a carbonate content of from 5 to 15%calculated as the weight percent CO₃ in the polyethercarbonate polyol.15. The method of claim 1, wherein step b) comprises reacting an alcoholinitiator with at least one alkylene oxide and carbon dioxide under apositive pressure in the presence of said multimetal cyanide compound toproduce a polyethercarbonate polyol having a number average molecularweight of from 200 to 20,000 Daltons.
 16. The method of claim 1, whereinstep b) comprises reacting an alcohol initiator with at least onealkylene oxide and carbon dioxide under a positive pressure in thepresence of less than or equal to 1.0% by weight based on the weight ofthe polyethercarbonate polyol of said multimetal cyanide compound. 17.The method of claim 1, wherein step b) comprises reacting an alcoholinitiator with at least one alkylene oxide and carbon dioxide under apositive pressure in the presence of less than or equal to 0.5% byweight based on the weight of the polyethercarbonate polyol of saidmultimetal cyanide compound.
 18. The method of claim 1, wherein step b)comprises reacting an alcohol initiator with at least one alkylene oxideand carbon dioxide under a positive pressure in the presence of lessthan or equal to 0.02% by weight based on the weight of thepolyethercarbonate polyol of said multimetal cyanide compound.
 19. Themethod of claim 1, wherein step a) comprises providing a multimetalcyanide compound having a crystalline structure and a content ofplatelet-shaped particles of at least 50% by weight, based on the weightof said multimetal cyanide compound and comprising at least two of thefollowing: an organic complexing agent, water, a polyether, and asurface-active substance.
 20. The method of claim 1, wherein step a)comprises providing a multimetal cyanide compound having a crystallinestructure and a content of platelet-shaped particles of at least 70% byweight, based on the weight of said multimetal cyanide compound andcomprising at least two of the following: an organic complexing agent,water, a polyether, and a surface-active substance.